/* adlist.c - A generic doubly linked list implementation
 *
 * Copyright (c) 2006-2010, Salvatore Sanfilippo <antirez at gmail dot com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *   * Neither the name of Redis nor the names of its contributors may be used
 *     to endorse or promote products derived from this software without
 *     specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdlib.h>
#include "appnet_list.h"
#include "zmalloc.h"

/* Create a new list. The created list can be freed with
 * AlFreeList(), but private value of every node need to be freed
 * by the user before to call AlFreeList().
 *
 * On error, NULL is returned. Otherwise the pointer to the new list. */
list *listCreate( void )
{
	struct list *list;
	
	if (( list = zmalloc( sizeof( *list ) ) ) == NULL)
		return NULL;
	list->head = list->tail = NULL;
	list->len = 0;
	list->dup = NULL;
	list->free = NULL;
	list->match = NULL;
	return list;
}

/* Free the whole list.
 *
 * This function can't fail. */
void listRelease( list *list )
{
	unsigned long len;
	listNode *current,*next;
	
	current = list->head;
	len = list->len;
	while (len--)
	{
		next = current->next;
		if (list->free)
			list->free( current->value );
		zfree( current );
		current = next;
	}
	zfree( list );
}

/* Add a new node to the list, to head, containing the specified 'value'
 * pointer as value.
 *
 * On error, NULL is returned and no operation is performed (i.e. the
 * list remains unaltered).
 * On success the 'list' pointer you pass to the function is returned. */
list *listAddNodeHead( list *list , void *value )
{
	listNode *node;
	
	if (( node = zmalloc( sizeof( *node ) ) ) == NULL)
		return NULL;
	node->value = value;
	if (list->len == 0)
	{
		list->head = list->tail = node;
		node->prev = node->next = NULL;
	}
	else
	{
		node->prev = NULL;
		node->next = list->head;
		list->head->prev = node;
		list->head = node;
	}
	list->len++;
	return list;
}

/* Add a new node to the list, to tail, containing the specified 'value'
 * pointer as value.
 *
 * On error, NULL is returned and no operation is performed (i.e. the
 * list remains unaltered).
 * On success the 'list' pointer you pass to the function is returned. */
list *listAddNodeTail( list *list , void *value )
{
	listNode *node;
	
	if (( node = zmalloc( sizeof( *node ) ) ) == NULL)
		return NULL;
	node->value = value;
	if (list->len == 0)
	{
		list->head = list->tail = node;
		node->prev = node->next = NULL;
	}
	else
	{
		node->prev = list->tail;
		node->next = NULL;
		list->tail->next = node;
		list->tail = node;
	}
	list->len++;
	return list;
}

list *listInsertNode( list *list , listNode *old_node , void *value , int after )
{
	listNode *node;
	
	if (( node = zmalloc( sizeof( *node ) ) ) == NULL)
		return NULL;
	node->value = value;
	if (after)
	{
		node->prev = old_node;
		node->next = old_node->next;
		if (list->tail == old_node)
		{
			list->tail = node;
		}
	}
	else
	{
		node->next = old_node;
		node->prev = old_node->prev;
		if (list->head == old_node)
		{
			list->head = node;
		}
	}
	if (node->prev != NULL)
	{
		node->prev->next = node;
	}
	if (node->next != NULL)
	{
		node->next->prev = node;
	}
	list->len++;
	return list;
}

/* Remove the specified node from the specified list.
 * It's up to the caller to free the private value of the node.
 *
 * This function can't fail. */
void listDelNode( list *list , listNode *node )
{
	if (node->prev)
		node->prev->next = node->next;
	else
		list->head = node->next;
	if (node->next)
		node->next->prev = node->prev;
	else
		list->tail = node->prev;
	if (list->free)
		list->free( node->value );
	zfree( node );
	list->len--;
}

/* Returns a list iterator 'iter'. After the initialization every
 * call to listNext() will return the next element of the list.
 *
 * This function can't fail. */
listIter *listGetIterator( list *list , int direction )
{
	listIter *iter;
	
	if (( iter = zmalloc( sizeof( *iter ) ) ) == NULL)
		return NULL;
	if (direction == AL_START_HEAD)
		iter->next = list->head;
	else
		iter->next = list->tail;
	iter->direction = direction;
	return iter;
}

/* Release the iterator memory */
void listReleaseIterator( listIter *iter )
{
	zfree( iter );
}

/* Create an iterator in the list private iterator structure */
void listRewind( list *list , listIter *li )
{
	li->next = list->head;
	li->direction = AL_START_HEAD;
}

void listRewindTail( list *list , listIter *li )
{
	li->next = list->tail;
	li->direction = AL_START_TAIL;
}

/* Return the next element of an iterator.
 * It's valid to remove the currently returned element using
 * listDelNode(), but not to remove other elements.
 *
 * The function returns a pointer to the next element of the list,
 * or NULL if there are no more elements, so the classical usage patter
 * is:
 *
 * iter = listGetIterator(list,<direction>);
 * while ((node = listNext(iter)) != NULL) {
 *     doSomethingWith(listNodeValue(node));
 * }
 *
 * */
listNode *listNext( listIter *iter )
{
	listNode *current = iter->next;
	
	if (current != NULL)
	{
		if (iter->direction == AL_START_HEAD)
			iter->next = current->next;
		else
			iter->next = current->prev;
	}
	return current;
}

/* Duplicate the whole list. On out of memory NULL is returned.
 * On success a copy of the original list is returned.
 *
 * The 'Dup' method set with listSetDupMethod() function is used
 * to copy the node value. Otherwise the same pointer value of
 * the original node is used as value of the copied node.
 *
 * The original list both on success or error is never modified. */
list *listDup( list *orig )
{
	list *copy;
	listIter *iter;
	listNode *node;
	
	if (( copy = listCreate() ) == NULL)
		return NULL;
	copy->dup = orig->dup;
	copy->free = orig->free;
	copy->match = orig->match;
	iter = listGetIterator( orig , AL_START_HEAD );
	while (( node = listNext( iter ) ) != NULL)
	{
		void *value;
		
		if (copy->dup)
		{
			value = copy->dup( node->value );
			if (value == NULL)
			{
				listRelease( copy );
				listReleaseIterator( iter );
				return NULL;
			}
		}
		else
			value = node->value;
		if (listAddNodeTail( copy , value ) == NULL)
		{
			listRelease( copy );
			listReleaseIterator( iter );
			return NULL;
		}
	}
	listReleaseIterator( iter );
	return copy;
}

/* Search the list for a node matching a given key.
 * The match is performed using the 'match' method
 * set with listSetMatchMethod(). If no 'match' method
 * is set, the 'value' pointer of every node is directly
 * compared with the 'key' pointer.
 *
 * On success the first matching node pointer is returned
 * (search starts from head). If no matching node exists
 * NULL is returned. */
listNode *listSearchKey( list *list , void *key )
{
	listIter *iter;
	listNode *node;
	
	iter = listGetIterator( list , AL_START_HEAD );
	while (( node = listNext( iter ) ) != NULL)
	{
		if (list->match)
		{
			if (list->match( node->value , key ))
			{
				listReleaseIterator( iter );
				return node;
			}
		}
		else
		{
			if (key == node->value)
			{
				listReleaseIterator( iter );
				return node;
			}
		}
	}
	listReleaseIterator( iter );
	return NULL;
}

/* Return the element at the specified zero-based index
 * where 0 is the head, 1 is the element next to head
 * and so on. Negative integers are used in order to count
 * from the tail, -1 is the last element, -2 the penultimate
 * and so on. If the index is out of range NULL is returned. */
listNode *listIndex( list *list , long index )
{
	listNode *n;
	
	if (index < 0)
	{
		index = ( -index ) - 1;
		n = list->tail;
		while (index-- && n)
			n = n->prev;
	}
	else
	{
		n = list->head;
		while (index-- && n)
			n = n->next;
	}
	return n;
}

/* Rotate the list removing the tail node and inserting it to the head. */
void listRotate( list *list )
{
	listNode *tail = list->tail;
	
	if (listLength(list) <= 1)
		return;
	
	/* Detach current tail */
	list->tail = tail->prev;
	list->tail->next = NULL;
	/* Move it as head */
	list->head->prev = tail;
	tail->prev = NULL;
	tail->next = list->head;
	list->head = tail;
}
